In this Nov. 3, 2013, file photo, the roof is open on the stadium before an NFL football game between the Dallas Cowboys and the Minnesota Vikings in Arlington, Texas. Forbes says Cowboys are the first U.S. sports franchise to top $3 billion in value. For the eighth straight year, the Cowboys are worth the most of all 32 NFL franchises, valued at $3.2 billion. (AP Photo/Sharon Ellman, File)
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